Tetracyclines In Water Samples Research Articles

Paper-Based Fluorescent Sensor for Rapid Multi-Channel Detection of Tetracycline Based on Graphene Quantum Dots Coated with Molecularly Imprinted Polymer.

In this paper, we developed a paper-based fluorescent sensor using functional composite materials composed of graphene quantum dots (GQDs) coated with molecularly imprinted polymers (MIPs) for the selective detection of tetracycline (TC) in water. GQDs, as eco-friendly fluorophores, were chemically grafted onto the surface of paper fibers. MIPs, serving as the recognition element, were then wrapped around the GQDs via precipitation polymerization using 3-aminopropyltriethoxysilane (APTES) as the functional monomer. Optimal parameters such as quantum dot concentration, grafting time, and elution time were examined to assess the sensor's detection performance. The results revealed that the sensor exhibited a linear response to TC concentrations in the range of 1 to 40 µmol/L, with a limit of detection (LOD) of 0.87 µmol/L. When applied to spiked detection in actual water samples, recoveries ranged from 103.3% to 109.4%. Overall, this paper-based fluorescent sensor (MIPs@GQDs@PAD) shows great potential for portable, multi-channel, and rapid detection of TC in water samples in the future.

Ratiometric fluorescent probes based on carbon dots and europium for rapid detection of tetracycline

Tetracycline (TC) is a typical emerging pharmaceuticals and personal care products (PPCPs) pollutants in the environment. However, TC residues cause severe effects on human health. It is crucial to exploit simple, rapid and sensitive methods to detect TC in water samples. A ratiometric fluorescent probes (CDs-Eu3+) is constructed using carbon dots (CDs) and europium ions (Eu3+) for the visual detection of tetracycline (TC). Under 390 nm excitation, CDs-Eu3+ shows a strong yellow fluorescence at 545 nm and a weak red fluorescence at 619 nm, respectively. In the presence of TC, the fluorescence intensity at 545 nm decreased while the fluorescence intensity at 619 nm increased, which attributed to the internal filtering effect (IFE) and “antenna effect”, respectively. Sensing performance of CDs-Eu3+ probes is further evaluated with respect to various conditions, including salt concentration, Eu3+ concentration, pH, and reaction time. Results reveal that the proposed ratiometric fluorescent probes exhibits a specific recognition ability toward TC. An excellent linear relationship is observed between the fluorescence intensity ratio (F619/F545) and TC concentrations (1⁓100 μM), with a low detection limit (LOD) of 31 nM. The solution (CDs-Eu3+-TC) color gradually changes from yellow to red after adding TC. The probes are successfully applied to determine TC in water with recoveries of 85.43⁓97.53%. Finally, a fluorescent test strip is prepared and used for rapid visual semi-quantitative TC detection.

Magnetic chitosan-zeolite composite as an adsorbent in ultrasound-assisted magnetic solid phase extraction of tetracyclines in water samples

An ultrasound-assisted magnetic solid-phase extraction method was developed to pre-concentrate tetracyclines (TCs) in wastewater and river water. The magnetic chitosan-zeolite composite was used as an adsorbent. The morphological and structural properties of the adsorbent were characterised by various analytical techniques. The factors affecting the ultrasound-assisted magnetic solid-phase extraction method were optimised using a central composite design. A high performance liquid chromatography equipped with a photodiode array detector was used to quantify TCs in wastewater and river water samples. Under optimised parameters, the developed analytical approach gave acceptable linearity (LOQ-400 µg L−1) with correlation coefficients exceeding 0.993, while the detection and quantitation limits ranged from 0.05–0.67 and 0.14–2.03 µg L−1, respectively. Attained recoveries were 90–101%, with intraday and interday precision expressed as the relative standard deviation (%RSD) below 5%. Even though the target analytes (tetracycline, oxytetracycline and oxytetracycline) were not detected in environmental samples, the synthesised adsorbent was suitable for the isolation of TCs in a complex matrix resulting in an accurate, precise, rapid and sensitive analytical method.

Response Surface Method for Simultaneous Separation of Non-Steroidal Anti-Inflammatory Drugs and Tetracyclines in Water Samples using Online Solid Phase Extraction-Liquid Chromatography

Response Surface Method for Simultaneous Separation of Non-Steroidal Anti-Inflammatory Drugs and Tetracyclines in Water Samples using Online Solid Phase Extraction-Liquid Chromatography

A simple paper-based nickel nanocluster-europium mixed ratio fluorescent probe for rapid visual sensing of tetracyclines

In this work, a ratiometric fluorometric sensor based on nickel nanoclusters (NiNCs)-europium complex (NiNCs-Eu3+) was constructed for the highly selectivity detection of tetracyclines (TCs) in water samples. In the presence of TCs, the blue fluorescence of the sensor NiNCs-Eu3+ was quenched at 430 nm and the characteristic red fluorescence of Eu3+-TCs appeared at 620 nm because of the combined help of inner filter effect (IFE) and antenna effect. Under the optimized conditions (100 mM Eu3+ (100 µL); temperature (25℃); reaction time (10 min), HEPES buffer solution (pH = 7.0)), the sensor offered a wide detection range of tetracycline (TC) and oxytetracycline (OTC) from 0.1 to 50 μM with the detection limit (LOD) of 25 nM and 21 nM, respectively. Moreover, the sensor was able to detect of TC and OTC in tap and lake water with high recovery rate (89.10%-97.60%). In addition, the portable paper-based sensor was constructed using filter paper embedded with NiNCs-Eu3+. The distinct fluorescent color of the paper-based sensor varied from bright blue to red against different concentrations of TC and OTC. These above findings demonstrated the potential for wide application of as-prepared ratio metric fluorescence sensor for visual detection of TCs in water samples.

Hierarchically porous zeolitic imidazole framework-8/cellulose membrane installed in filter as sorbent for microextraction in packed syringe towards trace tetracyclines in water samples

Zeolitic imidazole framework-8/cellulose membrane as a sorbent for lab-made microextraction in packed syringe towards trace tetracyclines in water samples.

Ratiometric fluorescent probe for tetracycline detection based on waste printing paper.

Tetracycline (TC) is a broad-spectrum antibiotic used to treat bacterial infections. In this study, a ratiometric fluorescence (FL) probe was developed to detect TC in water samples using waste printing paper extract as a FL indicator. For this ratiometric probe, the emission of printing paper extract at 436 nm gradually decreased and the emission of a mixed solution at 538 nm significantly increased with the sequential addition of TC upon excitation at 390 nm, coupled with a marked FL colour change from bright blue to faint yellow. Therefore, a ratiometric F538 /F436 FL probe was created for TC detection by simply mixing the printing paper extraction and TC. Under the optimized conditions, a linear range from 1 to 100 μM and a detection limit of 0.48 μM (S/N = 3) for TC were obtained. Importantly, the FL probe can be easily prepared with rapid response, high sensitivity, and good selectivity. The application of waste printing paper extract for detection of TC in environmental water samples was demonstrated.

A green dispersive liquid-liquid microextraction based on deep eutectic solvents doped with β-cyclodextrin: Application for determination of tetracyclines in water samples

A hydrophilic/hydrophobic deep eutectic solvent (DES) system was developed and used as a disperser/extraction solvent mixture in dispersive liquid-liquid microextraction of tetracyclines (TCs) in water samples. Five DESs were prepared, and their applicability was evaluated. Among them, [choline chloride]:[ethylene glycol] (a hydrophilic DES) and [thymol]:[octanoic acid] (a hydrophobic DES) showed the highest efficiencies as disperser solvent and extraction solvent, respectively. The addition of beta-cyclodextrin (β-CD) to the extraction phase led to enhance extraction efficiencies, probably through the selective supramolecular host-guest inclusion of TCs. Besides, β-CD improved the dispersibility of the extraction solvent and contributed to the formation of a very stable cloudy solution. The significant parameters of the extraction process were investigated and the optimal conditions were obtained as follows: extraction solvent ([Th]:[OA]), 175 µL; disperser solvent ([ChCl]:[EG]), 750 µL; β-CD, 5 mg; pH, 5; NaCl, 1% (w/v); and sample solution, 10 mL. Under the optimized conditions, the limits of detection were 1.37–4.38 µg L−1, and the linear range was 4.6–500 µg L−1. The greenness of the developed method was assessed using Analytical Eco-Scale and Green Analytical Procedure Index (GAPI). The proposed DLLME method was coupled with HPLC-UV technique and applied to the analysis of oxytetracycline, doxycycline, and tetracycline antibiotics in environmental water samples and satisfactory recoveries (74–113%) were obtained.

Hydrophobic deep eutectic solvent as a green extractant for high-performance liquid chromatographic determination of tetracyclines in water samples.

A green extractant, hydrophobic deep eutectic solvent was first introduced for extraction of tetracycline, oxytetracycline, and chlortetracycline from environmental water samples prior to high-performance liquid chromatography determination. Deep eutectic solvents consist of methyltrioctylammonium chloride and various medium-chain alcohols/acids, and are easy in preparation, low cost and toxicity, desirably biodegradable, and biocompatible. Theoveralltimerequired for sample preparation was 6min and the volume of organic solvent used for extraction was only 400µL. Under the optimized extraction condition, the present method yielded low limit of detection (0.5-2.0ng/mL), acceptable precision (relative standard deviations < 9.7%), good linearity from 2.0 to 500ng/mL (r2 ≥0.9991). This optimized procedure was applied for determination of tetracyclines in different water samples with desirable spiked recovery ranged from 77.5 to 87.6%. There is, therefore, a great potential to further expand application of the method for investigation of other ultra-trace analyte(s) in environmental matrixes.

Gold nanostars-enhanced Raman fingerprint strip for rapid detection of trace tetracycline in water samples.

Rapid and accurate detection of antibiotics at trace levels in food represents a great challenge. Tetracycline (TC), as a sort of broad-spectrum antibiotic, has been extensively used in animal infection therapy and animal husbandry as growth promoters. Large amounts of TC residues in animal-derived foods affect food quality and safety, and cause undesirable side effects such as allergic reactions and bacterial antibiotic resistance. Here, a Raman fingerprint strip sensor was reported based on surface-enhanced Raman scattering technology and demonstrated for ultrasensitive detection of TC. In this approach, 4-aminothiophenol (4-ATP) modified gold nanostars (GNSs) were used as a strong Raman reporter, which was coated with anti-TC monoclonal antibody serving as a biorecognition to acquire both visual and Raman signals on the test line. To demonstrate the performance of this strip, TC standard solutions with concentrations ranging from 0.5 to 50ng/mL was detected, the limit of the detection (LOD) for the Raman signal was 0.04ng/mL, which was 100 times more sensitive than those of color intensity quantifications. The other analogues, oxytetracycline, and chlortetracycline were detected using this method, making them suitable for the samples with TC analogues screening.

A tailored molecular imprinting ratiometric fluorescent sensor based on red/blue carbon dots for ultrasensitive tetracycline detection

The molecular imprinting ratiometric fluorescence sensor has exhibited great potential in biological and environmental detection because of the combination between the excellent selectivity of molecular imprinting technique and outstanding robustness of ratiometric measurement methods On this basis, two kinds of different well-resolved wavelengths and high-fluorescent carbon dots (CDs) were prepared by various solvent extraction using osmanthus fragrans leaves as carbon source. Then the ratiometric fluorescence sensor (MIPs@rCDs/bCDs@SiO2) has been constructed by the obtained CDs which the red-emission CDs (rCDs) were used to responsive signal and the blue-emission CDs (bCDs) was served as reference signal and applied for highly selective and excellent sensitive detection of tetracycline (TC). Under optimum conditions, the ratiometric fluorescence MIPs@rCDs/bCDs@SiO2 sensor has also exhibited lower detection limit of 1.19nM and the linear range of 0–50nM. The ratiometric fluorescence sensor was further successfully employed to the determination of TC in water samples gathered from local river water and tap water, indicating its great worth toward water sample analysis in complicated environments.

Dispersive magnetic solid phase extraction using octadecyl coated silica magnetite nanoparticles for the extraction of tetracyclines in water samples

Magnetite nanoparticles coated with silica and hydrophobic octadecyl layers were successfully synthesized and used in magnetic solid phase extraction of tetracyclines from water samples. The magnetite nanoparticles facilitated a convenient magnetic separation of sorbent from an aqueous sample, the octadecyl layer helped to enhance the adsorption ability and the silica layer helped to prevent the aggregation of the magnetite nanoparticles. The effect of various parameters on the extraction efficiency were optimized including the amount of sorbent, sample pH, stirring rate, extraction time and desorption conditions. Under the optimum conditions, the recoveries were in the range of 82 to 88%, the calibration curves were linear over the concentration range of 0.002 to 1.0 μg/mL for oxytetracycline and 0.01 to 1.0 μg/mL for tetracycline and chlortetracycline, respectively. The developed method had several advantages such as simplicity, convenience, cost-effectiveness and high extraction efficiency.

Application of molybdenum disulfide nanosheets for adsorption of tetracycline in water samples

Application of molybdenum disulfide nanosheets for adsorption of tetracycline in water samples

Trace determination of tetracyclines in water samples by capillary zone electrophoresis combining off-line and on-line sample preconcentration.

In this work, a sensitive and reliable method using capillary zone electrophoresis with UV detection has been developed for trace determination of tetracycline antibiotics in river, spring, and ground waters. A solid-phase extraction method using Oasis HLB was applied for off-line preconcentration and cleanup of water samples, in combination with an on-line preconcentration methodology named large volume sample stacking with polarity switching. Different parameters were optimized in order to obtain an adequate separation combined with the highest sensitivity, using 75 mM sodium carbonate (pH 10) and 1 mM EDTA as separation buffer, applying a voltage of 25 kV at 25°C. The samples were injected in water at 1 bar for 1 min, applying then -25 kV and starting the sample stacking. Sample matrix removal from the capillary was controlled by monitoring the electric current (when the 95% of the separation current is reached the stacking process is completed). The applied voltage was then switched from negative to a positive value of 25 kV in order to separate the compounds. Under optimum conditions, sensitivity enhancement factors ranged from 303 to 428 for the studied compounds. The combination of both off-line and on-line preconcentration procedures provided a total sensitivity enhancement factor about 20000, obtaining detection limits from 67 to 167 ng/L. The precision (intra- and interday), expressed as %RSD was below 12%. Recoveries obtained from river, spring, and ground waters ranged from 87 to 96%. Thus, this procedure is suitable for monitoring these compounds in water samples.

Determination of Tetracyclines in Water by Ethyl Acetate–Ionic Liquid Dispersive Liquid–Liquid Microextraction and High-Performance Liquid Chromatography

An ethyl acetate-assisted ionic liquid dispersive liquid–liquid microextraction method was developed for the determination of tetracyclines in water samples with high-performance liquid chromatography using a variable wavelength detector. A mixture of ethyl acetate and 1-butyl-3-methylimidazolium hexafluorophosphate was used to isolate lanthanum(III) chelates of tetracyclines. The addition of ethyl acetate significantly enhanced the extraction efficiencies. Experimental parameters affecting the efficiency such as the identity and volume of ionic liquid, the volume of ethyl acetate, chelating time, centrifuge time, pH, and ionic strength were evaluated. Under the optimum conditions, the calibration curves were linear and the correlation coefficients (r 2 ) ranged from 0.9985 to 0.9992 over concentration levels of 0.01–0.50 µg mL−1. The limits of detection (signal-to-noise ratio = 3) of the method ranged from 0.97 to 1.14 ng mL−1, whereas inter- and intra-day relative standard deviations (n = 5) were between 2.4–4.3% and 3.6–6.8%, respectively. This method was used to analyze water samples and recoveries from 62.6% to 109.6% were obtained.

Screening method for the determination of selected tetracyclines in water by liquid chromatography with diode array detector

Abstract A chromatographic procedure for determination of oxytetracycline (OXT), tetracycline (TC), chlorotetracycline (CTC), and doxycycline (DC) in water samples was developed and was applied for the analysis of water samples collected from poultry and pig farms and environmental water samples. Samples were acidified with trifluoroacetetic acid to pH 3 and further purified by solid phase extraction using Oasis HLB cartridges. The samples were dried up and redissolved in the mixture of oxalic acid and methanol. Separation was performed on reserved phase column (Phenomenex column C18 , 250 mm × 4.6 mm, 5 μm) by multistep gradient elution, and detection was carried out at 360 nm for OTC and TC, 370 nm for CTC, and 350 nm for DC. The tetracyclines were eluted with the mobile phase of 0.05 M oxalic acid (pH 2.5), acetonitrile, and methanol. This method provided average recoveries of 83.53% to 108.59%, with coefficient of variations (CVs) of 2.41% to 8.64% in the range of 10 to 1000 μg/L OTC, TC, CTC, and DC in water. The linearity for the tetracyclines was determined by HPLC-DAD in the range 10 to 1000 μg/L, with the correlation coefficient (R) &gt; 0.99. The LOD and LOQ for the tetracyclines in water samples ranged from 1.51 to 4.00 and 2.51 to 5.93 μg/L, respectively.

Direct screening of tetracyclines in water and bovine milk using room temperature phosphorescence detection

A fast and simple flow-through optosensor was designed and characterized for the direct screening of four tetracycline (TCC) antibiotics (tetracycline, oxytetracycline, chlortetracycline and doxycycline) in water and bovine milk samples. The proposed optosensor provides rapid binary yes/no overall responses, being appropriate for the screening of this family of antibiotics above or below a pre-set concentration threshold. The experimental set-up is based on a flow-injection manifold coupled on-line to a phosphorescence detector. Aliquots of the samples are pretreated with Eu(III) to form room temperature phosphorescent metal chelates and injected in the flow manifold. Those chelates are then on-line retained on a conventional flow-cell (packed with polymeric Amberlite XAD-4 particles) which is placed inside the cell holder of the phosphorimeter. After the emission is registered, the antibiotic–metal complexes are eluted from the packed resin with 1 M HCl (for milk samples a second regeneration step, using methanol, should be performed). A sample throughput of about 20 samples per hour was obtained. Optimum experimental conditions include a pH 9, a Eu(III) concentration of 2 × 10 −4 M and 8 mM sodium sulphite as chemical deoxygenant. The phosphorescence emitted by the europium–TCC complexes was measured at 394 and 617 nm for excitation and emission wavelengths, respectively. The unreliability region, given by the probability of false positives and false negatives, respectively (set at 5% in both cases) was in the range between 0.2 and 11.6 nМ for detection of tetracyclines in water samples (at a cut-off level of 4 nM) and in the range between 165 and 238 nM for detection of tetracyclines in milk (cut-off level fixed at the normative EU level of 200 nM). Finally, the applicability of the proposed screening optosensor was tested for the reliable control of tetracyclines in contaminated and uncontaminated water and milk samples.

Use of basic amphiprotic organic solvents containing neutral-surfactant aggregates as pseudostationary phase in non-aqueous capillary electrophoresis

A new approach to non-aqueous capillary electrophoresis based on the addition of anionic carboxylic surfactants to the basic amphiprotic organic solvent in which form neutral-surfactant aggregates was developed with a view to improving the electrophoretic resolution of charged substances. These aggregates acts as a new pseudostationary phase. The presence of these aggregates allows the effective separation of four tetracyclines with increased selectivity. The efficiency of sodium caprylate, sodium laurate and sodium palmitate as surfactants was examined. The latter two proved more effective than the former as they provided migration times reproducible to within 7% or better in all cases. The additional use of an alcohol allows peak shape to be controlled, which expands the potential of this electrophoretic technique even further. The proposed method was used to determine tetracyclines in water samples. The sensitivity of the determination was improved by using a flow manifold coupled at-line to the capillary electrophoresis system in order to preconcentrate the analytes. The limits of detection thus achieved ranged from 50 to 90 μg/l. Under optimal operating conditions, recoveries ranged from 97 to 104%, and precision from 5.4 to 7.0%.

Determination of Tetracyclines in Water Samples Using Liquid Chromatography with Fluorimetric Detection

A liquid chromatographic method with fluorimetric detection is proposed for the determination of trace levels of oxytetracycline, tetracycline, chlortetracycline and doxycycline in water samples. The analytes are preconcentrated by solid phase extraction using reversed phase polymeric cartridges and acetonitrile as eluent. Preconcentration factors up to 125 can be obtained. The chromatographic separation is performed on a polymeric column with a gradient elution program using mobile phases based on mixtures of acetonitrile and 0.01 mol L−1 oxalic acid aqueous solution at a flow rate of 1.2 mL min−1. Tetracyclines are post-column derivatized with a reagent solution consisting of 0.1 mol L−1 Mg(II) at pH 9 at a flow rate of 0.6 mL min−1. The highly fluorescent Mg(II) chelates are detected at λ ex = 374 nm and λ em = 499 nm. The detection limits of the whole process are in the low μg L−1 level. The proposed method has been applied to the analysis of spiked natural water samples, and recovery rates higher than 80% have been obtained.